Method and means for cooling electrical apparatus



July 17, 1923. 1,462,321

L. H. BURNHAM METHOD AND MEANS FOR COOLING ELECTRICAL APPARATUS FiledJan. 20 1922 law HES Attorne Patented duly i323 mi e unirnn FLGlCIKE H.BURNHAM. G? PI'I'ESE'IELD, PEAS "is it.

ACH'UfiE'JiTS, ASSIGNOR TC METHOD AND MEANS FUR EOGIZENG ELECTELIGALAPFfiISLAT'tJ'S.

Application filed January 263,

To all w/mm it may concern:

Be it known that l. liociii: lil'RNlIAMK a citizen of the l nitedritates. residing at Pittsfield. in the county of Berkshire. State ofMassachusetts. have invented certain new and useful lmproveinents inMethods and Means for tooling Electrical Apparatus. of which thefollowing is a specification.

My invention relates to the cooling of clcctrical apparatus and itsgeneral object is to provide an improved method adapted for thispurpose. and an improved means for practicing this method. Some types ofelectrical apparatus develop a considerable amount of heat duringperiods of normal operation and this heat must be dissipated at aSuthcient rate to prevent such an increase in the temperature of theapparatus as might cause injury. It is often true that the maximum safeload which a piece of electrical apparatus can carry may be increased byincreasing the rate at which the heat generated in the apparatus isdissipated.

In connection with electrical apparatus which may generate anundesirable amount of heat, it is customary to provide some specialarrangement tor dissipatin the excess heat. It is a particular object ofthe present invention to provide an improved method and apparatuswhereby cooling currents of air may be induced and caused to come intocontact with heat radiating surfaces which have received heat from theelectrical apparatus: these surfaces giving up the heat to the movingair which acts eiiiciently to prevent undesirable temperatures in thelectrical apparatus.

One type of electrical apparatus in connection with which my inventionis adapted to be used with advantage is found in static transformersand. although the advantages of the invention for other purposes will beapparent. this embodiment thereof is explained in the followingdescription and in the accompanying drawing in which Fig, 1 shows inelevation a static transformer equipped with heat radiators and withcooling means arranged in accordance with my invention; Fig. 2 is a planview of apparatus shown in Fig. 1 with a blower and its motor omitted,and Fig. 3 is a plan View of one ofthe radiators with part of thecooling apparatus of my invention, a portion of the top of the radiatorbeing broken away.

Serial Ii'o. 53),738.

Like reference characters refer to similar parts in the differentfigures ot. the drawing.

in the embodiment of the invention shown in the drawing. a statictransformer 1. including the transformer proper and its surroundingcasing or container. is equip ed with a plurality of heat radiators 2.As is customary. the casing of the transformer and the radiators andconnections are filled with a suitable cooling and insulating mediumsuch -as an oil of high dielectric strength. the heat generated in thetransformer causing a thermal circulation of the cooling medium throughthe radiators where this heat is transferred to the surroundingatmosphere. and dissipated.

An air blot 'er 3 driven by a motor 42 supplies air under pressure to amain feed pipe 5 which in turn supplies this air to distributing pipes6. (in each side of each radiator 2 is a delivery pipe 7 which issupplied with air under pressure from the distributing pipes 6. Each ofthese delivery pipes 7 is provided with a series of small openings 8through which the air from within the pipe is blown in small currents orjets as indicated in Figs. 1 and 3. The openings 8 in each of the pipes6 are so positioned to direct the jets of air upwardly and inwardly aainst. the adjacent side or face of the radiator and therefore at anacute angle thereto. It is preferable that the openings 8 be spacedalong the pipes '3 so as to direct the air jets between the tallies ofthe radiators and thus distribute the moving air over a large radiatingsurface.

The jets of air issuing from the openings 8 draw along with them byfriction large volumes of air from the space below and atthe sides ofthe delivery pipes 7 as indicated by the arrows in Fig. 1 so that bylocating these pipes 7 at some distance above the lower ends of theradiating surfaces, the volume-0t air passing over the heat radiatingsurfaces may be several times as great as that issuing from the openings8 and supplied by the blower 3. A considerable radiatin surface belowand therefore behind the; jets of air being blown from the openings 8may be efficiently cooled by the air which is being drawn upwardlytoward the jets. After this air reaches the jets, the air from bothsources mingles and passes on under the influence of the jets to coolthe much greater quantity of moving air than that actually supplied bythe blower. It follows that a blower large enough to supply all the airnecessary to cool a given surface may be used in the cooling system ofthis invention to cool several times as great a surface. Heat radiatingbodies have sometimes been surrounded by flues through which air hasbeen passed from blowers to absorb heat. lVith such an arrangement,however, a blower must furnish all the air required. It has been foundthat in practicing my invention, at least three or four times as, muchradiating surface may be cooled by the same blower. This system ofcooling is useful in locations where water is not plentiful and it alsohas the advantage, even where water is plentiful, that.it is not subjectto trouble such as may be caused by leaks in coils cooled by water. Insame cases, the electrical apparatus is subject to Widely fluctuatingloads and there fore the amount of heat generated "aries widely. Undersuch conditions, it may hapen that during part of the time the radiatmgsurfaces may be cooled sufficiently by the natural circulation of thesurrounding air so that the blower may not be needed and ma be stopped.

at I claim asnew and desire to secure by Letters Patent of the UnitedStates, is:

1. In a method for cooling a radiating surface, the step which consistsin inducing and l directing a plurality of jets of air through and incontact with a surrounding body of ,air and toward the radiatingsurface, the paths of said jets being at acute angles to the generalplane of the surface, whereby air from said surrounding body of air iscarried with the air of the jets along said surface in front of thejets.

2. In a method for cooling a radiating surface, the step which consistsin inducing and directing a plurality of jets of air through and incontact with a surrounding body of air, said jets being directed towardone portion and away from another portion of the radiating surface, thepaths of said jets' being at acute angles to the general plane of thesurface, whereby air from said sur rounding body of air is moved alongthe portion of said surface behind the jets and thereafter with the airof said jets along the portion of said surface in front of said jets.

3. A cooling apparatus including a device having a radiating surface,means for supplying air under pressure, and means for directing aplurality of jets of said air through and in contact with a surroundingbody of air and against the radiating surface at acute angles to thegeneral plane of said surface.

4. A cooling apparatus including a device having aradiating surface,means for supplying air under pressure. and means for directing aplurality of jets of said air through and in contact with a surroundingbody of air. said jets being .directed toward one portion and away fromanother portion of the radiating surface. the paths of said jets beingat acute angles to the general plane of the surface. whereby air fromsaid surrounding body of air is moved along the portion of said surfacebehind the jets and thereafter with the air of said jets along theportion of said surface in front of said jets.

In witness whereof, I have hereunto set my hand this 18th day of Jan,1922.

LOCKE H. BURNHAM:

